The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Internal combustion engines combust an air and fuel mixture within cylinders to drive pistons, which produces drive torque. Air flow into gasoline engines is regulated via a throttle. More specifically, the throttle adjusts throttle area, which increases or decreases air flow into the engine. As the throttle area increases, the air flow into the engine increases. A fuel control system adjusts the rate that fuel is injected to provide a desired air/fuel mixture to the cylinders. Increasing the amount of air and fuel provided to the cylinders increases the torque output of the engine.
A vehicle may include an auto stop/start system that increases the vehicle's fuel efficiency. The auto stop/start system increases fuel efficiency by selectively shutting down the engine and disabling the flow of fuel to the engine while the ignition system of the vehicle is ON. While the engine is shut down, the auto stop/start system automatically starts the engine when one or more start-up conditions are satisfied.
In some circumstances, battery voltage dips during an auto start event after an auto stop event. While some systems such as an engine controller may be designed to handle the battery voltage dips, other vehicle systems such as a transmission controller or other controllers may not be as robust. When the battery voltage dips during an auto start event, these other controllers may enter into a reset mode of operation and/or cause other drivability issues.
Existing controllers for ultra-capacitor systems used for auto stop/start systems employ a two state diagnostic code for components within the system. The first state corresponds to “not failing” and the second state corresponds to “failing”. Current on-board diagnostic (“OBD”) regulations require diagnostic systems to report using diagnostic states including “pass”, “fail” and “indeterminate”. The “not failing” state is insufficient since it includes both “pass” and “indeterminate” states.